Normal paraffin waxes produced either from Fischer-Tropsch hydrocarbon synthesis or as a result of dewaxing oils, e.g., lubricating oils, are valuable starting materials for a variety of processes. The lack of sulfur or nitrogen contaminants in these materials makes them particularly desirable where high purity hydrocarbons are required. However, these materials are difficult to transport because they are solid at room temperature. Fischer-Tropsch waxes, for example, may be produced at remote sites and refined at existing refineries in industrialized areas. In order to move the wax to the refinery, the wax must be pumpable, thereby reducing transportation costs. One way of achieving the pumpable form of the wax is to isomerize the normal paraffins produced by the process to a more branched product that is liquid at room temperature, and therefore, more easily transportable.
Isomerization processes are well known and are usually conducted in the presence of hydrogen and a suitable isomerization catalyst at isomerization conditions, which include elevated temperatures and pressures.
As recently reported, see U.S. Pat. No. 4,832,819, hydroisomerization catalysts useful for the purposes disclosed herein contain platinum, fluoride, and alumina. However, fluoride tends to be stripped from the catalyst with use and makeup fluoride must be added constantly to the reaction zone for maintaining activity and selectivity of the catalyst. Also, environmental concerns favor replacing fluoride containing materials where there is any tendency for the fluoride to escape the refinery as a fluorine containing gas.
Also U.S. Pat. Nos. 3,843,509 and 4,139,494 describe silica-alumina materials that are useful, and preferred as the support materials for this invention, the disclosures of which are hereby incorporated by reference. Preferred materials are also shown in U.S. Pat. No. 4,837,193, the catalyst description thereon being incorporated herein by reference.